This invention relates to improved electronic wristwatches, and in particular, to the provision of an electronic calculator capability within a wristwatch. In the art, wristwatches driven by electric and electronic means and powered by batteries, hereinafter generally referred to as electronic wristwatches are achieving gradually increasing acceptance. Further, electronic wristwatches are now becoming known wherein time is displayed in a digital form. Generally, light-emitting diodes or liquid crystal displays are the most popular forms of such digital displays. With the development of digital displays capable of operation at low power, it is expected that such digital displays will achieve wider acceptance since they are the most direct and effective devices for indicating time.
Electronic wristwatches provided with digital displays generally have six digits of numerical display, two of the digits displaying hours, two of the digits displaying minutes and two of the digits displaying seconds. The digital display is generally positioned on the dial at the surface of the time piece.
With the development of digital displays, miniaturization of the circuits of electronic wristwatches have been subjected to detailed study. Such circuits generally consist of a crystal oscillator for producing a high frequency time standard signal, a chain of frequency divider circuits for reducing the time standard signal to timing signals and driving circuitry for driving the display. At the present time, an electronic wristwatch incorporating a crystal oscillator, and a fifteen step frequency divider wherein the time standard frequency of 16,384 Hz is divided into 0.5 Hz, can be produced in a chip of 0.5 of mm. around. Thus, with the miniaturization of the electronic circuit presently occupying most of the space in the timepiece, additional space is provided sufficient for the provision of other electronic circuits within the case. It is proposed to utilize this space for incorporating a calculator within an electronic wristwatch.